Intercommunication telephone system



Jan. 13, 1931. 5. B. KNOs I1789,142

INTERGOMMUNICATION TELEPHONE SYSTEM Filed March 29. 1929 2 Sheets-Sheet 1 Q16 KniiS Jan. 13, 1931. G. B. KNOS 9, 4

INTERCOMMUNICATION TELEPHONE SYSTEI I 7 Filed March 29. 1929 2' Sheets-Sheet 2 i /N Vern-2w r Patented Jan. 13, 1931 I f 1,789,1421 g emmsssmmas,,oF- memom; SWEDEN; assienon' v'1:0'aEran?61min:in ;o'nae'nr L la, .nmossongoii sTocKHoLM, swn'nnn, in COMPANY onijswnnnn l 7 inrnnoomiyrnmcnmion zrnnnrnonnsysmnivr a ncatin mi March 29, 1'929,' Sei ia1 No.35131171,and in'sweden ar her; 192s.-

The :present invention relates to intercom 'munication telephone systems. 1 More especially,:.it refers to such systems which are calledchief telephone systems and which in Vgeneralfare chairacterizedfby that the telephone apparatus are divided intochie'f apparatus and subordinate apparatus the former 0f 'wliich the chief apparatus are provided with loudspeakers and highly seni Sltfl'ilGplHlCl-OPhOIlGS, in order/to facilitate conversations :at a comparatively great. dis- ;tance fnoni the apparatus whereas the subondiinate-fapparatus, have no loudspeaker-s andusuall'y aref'arra-n ged as extension apiparatusin relation to the chiefapparatus,

Esa'id extension apparatus being not able to comnnu'ricate mutually among themselves. The present invention is substantmlly characterized Eby that the system @GOBJFBISBS three 120 kinds. of appanatus -wh-ich mayqbe called- Tchiefapparatus,sub-chief apparatus. and for- -;dinary, apparatus and among which the chief and sribmhiefi apparatus are in known mane-' ner {provided with loud-speakersand sensitive micmphones while the sub-chief (apparatus also :ane provided with" a speaking apparatusv 1 of ordinary type independent (ii-the loud; speaker, by way of example a hand microphone, which latter is adapted to be connected 31) into circuit duringconversation with a chief apparatus while the loudspeaker and ;the Sensitive in'icrophone in the sub-chief apparatus' areintended-to be usedduring conversa tion with a subordinate apparatus, ,sueh a 35 system has centain advantages incomparison with previously known systems amongwhich .aadvantages thefollowin'gniay be mentioned. -In the chief telephone apparatus the loud- 1 speaker and the sensitive microphone may he 40 used when talking with allthe other apparatus. .In previously known systemsboataie talking persons, if they are in possession apparatus provlded with loudspeakers, niust use hand receivers because the talking currents pro duced-bythe sensitive microphones arenot sufiiciently strong toactuate a loudspeaker, On;the other hand, inas'ysteinae cording to the invention in which the subchief apparatus are provided with a special speaking; set for conversation with the chief talking line circuits with the aid of switches line's "of i'alltthe' subordinate apparatus.-

' switches or keyse Th ectalkiiig c-onn'ections are be shifted froin thenorinal positionshown'on ,the drawing into a signalling position by apparatus, the microphone :of said speaking set anay-heofsuch a typethat the loudspeaker v of the chief apparatus may be vactuatedby sufiiciently strong ---'c ur rents. The system :has 7 further the advantage that a sub-chief when 455 talkingto the chief may communicate with asubordinateapparatus withoutiiinterrupting V the communication with the"chief-apparatus V in order to :gather --ilnifonmaitions the coversa tion with the subordinateapparatus being 'then held without using the -lo udspeaker 'and the:sensitivefniicrophone; The two speaking sets of the suh chief-xapparatus "are for this purpose adapted to be connected independ- :ently of each other into the' -corresponding or keys individual 1i30"tl l6f:ll n6S, the systein @heing. arranged in suchia' way, that the hand microtel'epthone is connected into circuit, over the switches 'appertaining' to {the-line of the chief 'apparatus wihereasthe loudspeaker and r the sensitive microphone are connected into circuit oyer-flie switches appertaining to the The inventioniwill he more closely (16-, n scr bed with reference 'to the accompanying local"telephoneisystemraccordingto the-inven- V :tio'n. The drawingsareintendedto be placed beside each other, Fgu re =1'hei'ng on -the right hand side' oiQFigure241 The::drawmgsQshow-the connections 'hetween the three: chief te l'ephonefapparatus A, B, (1,]and a suhordinate-telephone apparatus 11 'All theiapparatus are provided with established by means of switches A0, 5130,

C'Q-ZDQ which are individual tot he different 3 wire talking lines TL. Theasjwitches may throwiar theswitch downwards and also into.

,atalking position throwing the switch upwards; These 7 positions are indicated on the drawings icy-dashed and dottedlines.

The chief apparatus A, B, C are allprovided with a loudspeaker MT -and two semescoirnected sensitive microphones M- which ordiv narily areinounted together vwith. the switches in an apparatus loox. v Said'loudspeakers and 400 ordinate to the apparatus Awhich latter is V microphones are intended to be used when sion apparatus in relation to the chief apparatalking with a subordinate apparatus which psi t(l11en using a microtelephone of ordinary In the shown embodiment the chief apparatus aresubdivided into chief' and sub-chief apparatus as the apparatus Band C are subt e ea c f appar tu e app us B a C' being-then called sub-chief apparatus,

hen talkingbetween the apparatus A and any of theapparatus B and G these latter. are using a'microtelephone MT or MT respectively of ordinary type. Thechief apparatus A' normally uses the loudspeaker but, if desired instead a telephone receiver HL may be connected into circuit. The switching over is effected by means of a switch disposed in connection with the hook HO on which the tele phone receiver HL is placed in such a way 7 that the loudspeaker HT is disconnectedand the telephone receiver HL is conn'ectedinto circuit when removingthe lattenfrom the hook HO. The apparatus D is'o'nly provided with a hand microtelephoneltlTi; 1

Each apparatus isprovided with an optic signalling device AS; B'S,.CS or- DS respectively individual to each line in-theformof.

. an electromagnetic-ally actuated signalling shutter orthe like. Furtheran acoustic signalling device RS in the form of a call bell as disposed in common to all the lines. -The I apparatus A, B and G are also provided with a buzzer signalling device SS. The signalling devices RS and SS may be connected into circuit and disconnected by means of a switch S0 shi ftable into three positions. In the normal middle position-of the switch as shown (on the drawing the buzzeresignal SS is connected into circuit. By throwing the switch j down the call bell BS is instead connected into circuit. In the upper positionof the switch SQthe signalling devicesRS andSS are both 7 dlsconnectedonly the signalling'shutter being then operative to annoi'mce callsr Theapparatus A, B and C are-furtherprovidecl with a warning lamp SL which automatically is connected into circuit and lights. as soon as any of the'switchesAO, BOor COrespective- 'ly' are shifted to'the talking position. Fur- .therth'e apparatus A, B, C are cachprovided V with aspecial talking batteryTB :which nor mally is disconnectedfrom the talking Zwires phones'Mand the loudspeaker HT by shiftR but at a conversation with-subordinate ap- .paratusis connected into the corresponding talking circuit together with the'microtel'eing the correspondingswitch into talking position; Forsignalling a battery SB common to all the apparatus is used. The subordinate apparatus D has no special talking battery.

. Figure 1 shows onlya subordinateapparatus D although'usually several apparatus of this kind are used. Accordingto the shown c rcuit dlagrani they are arranged asfextenanother.

tus as they are able to talk only with the chief apparatus A, B, C but not mutually with one withthe shutter magnet. After sending a call'thecaller shifts hisswitchCO into talking position the talking battery TB the microphones M and the loudspeaker HT- being then connected into Ithetal ing circuit. When interrupting thesignalling circult 1 the bell RSgceases to call whereas the signalling shutter remains in callingposition.

In order to answer-the calls the switch D0 is shifted'to talking posit-ion theshutter magnet and the call bell being'then disconnected and the microphone 'MT instead connected int-o circuit; At thesame time, the shutter is restored to normal position by being mechanically actuated by the switch DO;;. The talking connection is'then'completed. The

talking'circu'it is arrangedin such a manner that the loudspeaker of th'eapparatus C'and the microphone of' the apparatus D areconnected in series into the line branch c1 rcuit b vwhereas the microphones of-the apparatus G andthe telephone receiver of the apparatus D sation connected in parallel with the talking are-included in series-inf th'e line branch a. The line bra-n'ches'a' and b are-during convex battery' TB the branclicbeing then used as iareturn wire. i A talking connect on between the 'appara-' tusD and any of the other subordinate apparatus-on account ofa' call sent from these 'l'atter is' est-ablishediin a completely analogous manner. Also a connection-between the chief apparatus A andany of the "apparatusB or C is established in same manner as just'de-V scribedfTh'e apparatus Band C as above described amusing, however,*the microtelephones MTgfor MTg -respectively which'are connected into circuitf: over contacts-in thecorresponding' switches B0 or CO respecv tiv'ely' wh'enisaid switchl is shifted to the talking 'p'ositio'nl The loudspeaker and the sensitive microphone I-IT M or' HT M are,

onthe other hand; intended 'to'be used-iwhen talking'with subordinate apparatus and are connected into circuitby way of example when talking with the apparatus D over the switch B0; or CO when'establishing connection between theapparatus- B or G- the apparatus B may usetheloudspeaker whereasthe apparatus Gmustuse the microtele phone ML. The apparatus canthus be considered as subordinate to the apparatus B.

The establishment of a talking connection upon a call from a subordinate apparatus to an apparatus which is a chief one 1n relation to the former one is efiected in a similar manner as at a call from a chief toa subordinate. When calling by way of example from the apparatus D to A, initially, the switch D0 is shifted to the signalling position a signalling circuit 3 being then "closed over the line branches or and 0 and through the signalling shutter A5 The lat-' ter connects over its contact 4 the buzzer signal SS or the call bell RS into circuit. The call is answered in the apparatus A by shifting the switch AO into talking position the signalling device being disconnected and the battery TB the microphones M and the loudspeaker I-IT being then connected into the circuit of the line' TL c I claim 2- w 1. Intercommimication telephone system comprising a number of chief-telephone apparatus provided with loudspeakers and sen'-' sitive microphones, a number of sub-chief apparatus provided witha speaking set con- SlSillIlg ot a loudspeaker. and a sensitive m1- crophone and in addition thereto a speaking set of the ordinary type independent of said I first mentioned speaking set, anumber of subordinate apparatus, means to connect said sub-chiefs ordinary speaking setfinto circuit upon establishing connection with "a chief apparatus and means to connect'the loudspeaker and the sensitive microphoneinto circuit upon establishing connection with a V subordinate apparatus.

r set of theordinary type independent of said firstmentioned speaking; set, a number of 2. Intercommunication telephone system comprising anumber of chieftelephone 'apparatus provided with loudspeakers and sensitive microphones, a number of sub-chief sisting of a loudspeaker and a sensitive microphone and in addition thereto a speaking subordinate apparatus,.telephone lines interconnecting said apparatus,switches at the i sub-chief apparatus individual to the chiefapparatus lines and adapted to connect up the ordinary speakingset of the sub-chief apparatus upon establishingjconnection with a corresponding chief-apparatus and other switches at the sub-chiet apparatus indi- 'f vidual to the subordinate apparatus lines and adapted to connect up the loudspeaker A and sensitive microphone of the sub-chief apparatus upon establishing connection with a corresponding subordinate apparatus;

In testimony whereof I aflix my signature.

GUNNAR 'BORJE KNGS; 

